To understand the mechanism of crown development in canopy trees under the annually varying reproductive allocation, the effect of foliage mass on the elongation of the branch axis in the upper part of the crown was examined each year for a 13-year growing season in Abies sachalinensis in a cold temperate forest in southwestern Hokkaido, Japan. Generalized linear models were used to examine the record of elongation of the main stem and branch axes. For foliage mass, indices using the past main-stem volume were calculated from the main-stem elongation records. Branch-axis elongation was investigated for 3-, 4-, and 5-year-old branches each year. The elongation records were investigated for 8 canopy trees whose branches from the crown top to at least 13-year-old branches had elongated in the sunlit space each year. According to the remaining seed-cone rachises, seed-cone production was large in 2000, 2008, and 2011 and small in 2002 and 2005. A positive effect of foliage mass on branch-axis elongation was detected for the 3- to 5-year-old branches in 2004 and 2005, but only for 3-year-old branches in 2003. The effect of foliage mass on branch-axis elongation in the upper part of the crown might be reduced by large amounts of reproduction.